Low-intensity pulsed ultrasound promotes spinal fusion by regulating macrophage polarization

作者：Zicheng Zhang, Yilin Yang, Bo Li, Xu-Ce Hu, Shuai Xu, Fei Wang, Ming Li, Xiaoyi Zhou, Xianzhao Wei · 发表于：Biomedicine & Pharmacotherapy · 年份：2019 · DOI：10.1016/j.biopha.2019.109499 · 被引用次数：48 · 研究领域：Management of metastatic bone disease、Ultrasound and Hyperthermia Applications、Cervical and Thoracic Myelopathy

BACKGROUND: Spinal fusion is considered the gold standard procedure for treating spinal degeneration, tumors, and trauma. An inflammatory response is an important part of bone repair. We investigated the polarization change of inflammatory macrophages (M1) and resident macrophages (M2) during low-intensity pulsed ultrasound (LIPUS) treatment. METHODS: Thirty male Sprague Dawley rats (age: 12 weeks; weight: 300 g) were used in the study. A rat spinal fusion model was established by surgical procedures. LIPUS treatment (20 min. d, 5 d/wk) was begun 3 days after surgery. The rats were randomly divided into a control group (5 subgroups, 3 rats in each subgroup) and LIPUS group (5 subgroups, 3 rats in each subgroup), and sacrificed on day 3, 5, 7, 10, and 14 after spinal fusion surgery for further evaluation. Bone volume was measured by micro-CT, fusion region was examined by histological analyses, types of macrophages in the fusion area were examined by immunohistochemical staining. Raw264.7 cells and bone marrow-derived macrophages (BMDM) were used in cell experiments. Cells were divided into a control group and LIPUS group. Flow cytometry was used to examine the rate of resident macrophages, and real-time PCR was used to examine the mRNA expression of anti-inflammation genes. RESULTS: macrophages (M2) were significantly increased after LIPUS treatment. M2-related genes and anti-inflammation factors (Arg-1, PPAR-γ, and IL-4) were increased after LIPUS treatment. CONCLUSION: The ...